Manufacture of filaments and films from viscose



Patented Jan. 11,1927.

UNITED STATES WILLIAM MENDEL, F

PATENT OFFICE.

MANUFACTURE OF FILAMENTS AND FILMS FBOM'ITISCOSE.

No Drawing. Application filed May 9,

, viscose (cellulose sulphocarbonate) through orifices into bathscontaining chemicals which coagulate the viscose as aasemi-solid impurecellulose hydrate of sufficient strength to be handled, and an objectand'effect of this invention is to eliminate the impurities from suchcoagulated cellulose hydrate and thus improve the luster, strength andelasticity of the finished filaments.

Such coagulating or' precipitating baths heretofore employed are ofvarious kinds.

For instance, because oftheir prompt actionand relatively low coststrong acid baths, such as an aqueous solution containing eight per centof sulphuric acid or five per cent of hydrochloric acid are commonlyused for individually thin filaments such as are used in the productionof artificial silk. With baths of that character, substantially all ofthe sulphur primarily chemically combined with the cellulose in viscoseis released as free sulphur but is occluded in the mass of. cellulosehydrate and impairs every desirable quality of the finished product; itbeing impossible to more than partially remove sulphur and itsderivatives from the celllulose hydrate by the ordinary processes.Consequently, filaments thus formed have a dull yellow white surface andare comparatively Weak and brittle. Organic acids and inphur and itsderivatives, and with the effectthat the effects of free sulphur aresomewhat less apparent, but the increased cost of such additionalchemicals and treatment is not economical because processes forcleansing the filaments are yet required, as in the caseof the strongeracids. Y

" .duced in such bathsin I have, discovered that if any. suitablecoagulating bath is made to include the PO,-

1011, filaments of cellulose hydrate formed .in such bath arepractically sel -cleansing because the sulphur derivartives are therebthe disadvantages of thelusual presence of ble sulphidesyare thusautomatically eliminated. I Such ions may be added to orproanyconvenient form or manner. However, tri-sodium phosphate with 2. The

1925. Serial No. 29,9828.

(Na,,PO,) is a cheap vehicle for such ions and may e used in aqueoussolution.

Although an aqueous solution of either mono-sodium phosphate ordi-sodium phosphate'or said tri-sodium phosphate alone W111 efl'ectcoagulation of viscose projected therein, particularly if the viscose isof low alkalin ty and such solution be hot; even a small percentage,approximating a'. mere trace of the 1on PO, is suflicient in associationor conjunction with any other suitable coagulating material. Forinstance, an aqueous bath containing ten -per cent of sulphuric acid(H', S O,) and containing ten per cent of sodlum sulphate (Na,SO,) is anordinary coagulating bath which is subject to the objections' aforesaid,but I find that the addition of even a fraction of one per cent of P0 tosuch bath has the advantageous results above contemplated in theelimination of or prevention of formation of, insoluble sulphurderivatives in or upon the cellulose products.

Filaments thus coagulatedin accordance my .invention mayv require nosubsequent treatment other than rinsing with ,water and, when so treatedand dried, preferably under tension, have unusually high luster,strength and elasticity.

Therefore I do not desire to limit myself to. the precise details ofconstruction, arrangement or procedure herein set forth, as it isobvious that various modifications may e made therein without departingfrom the essential features of my invention, as de-.

fined in the appended claims.

I claim:

1. The methodof manufacturing articles from viscose which consists incoagulating viscose in an aqueous solution in which trisodium phosphate,(N a PO,) has been dissolved with another solute ing such coagulation.

method of manufacturing articles capable of affectfrom viscosewhichconsists in coagulating 100 viscose in an aqueous solution in whichtrisodium phosphate -(Na PO has been disy .-solved ,-with an acid saltsolute, capable of rendered soluble in the bath; so that all of Y 50sulphur and its derivatives, such as insoluaffecting such coagulation.3; The method of manufacturing articles from viscose which consists incoagulating viscosein an aqueous-solution in which trisodium phosphate(Na POQ has been dissolve'd,with an acid solute capable of affectingsuch coagulation.

4. In the manufacture of cellulose articles from viscose(sulphocarbonate), the introduction of the latter into an aqueoussolution resultant from mixture of Water with an inorganic acid andtri-sodium phosphate.

, 5. In the manufacture of cellulose articles from viscose(sulphocarbonate), the introduction of the latter into an aqueoussolution resultant from mixture of Water with a strong mineral acid andNa PO 6. The method of manufacturing articles from viscose Whichconsists in coagulatingviscose in an aqueous solution comprising Na PO7. The method of forming from cellulose sulphocarbonate a semi-solidcomposition which is principally cellulose hydrate, and free fromdeleterious sulphur compounds; which consists in coagulating liquidsulphocarbonate in an aqueous solution including an efiicient acidcoagulating agent, and P0 ions in such relation With sodium phosphate asto extract such compounds from the sulphocarbon'ate into said aqueoussolution and prevent recipitation of such com ounds, by holding them insaid solution, in epend-.

ently of said cellulose hydrate.

' 8. The method of preventing formation of insoluble sulphur compoundsduring the coagulation of cellulose sulphocarbonate; which consists inprecipitating liquid cellulose sulphocarbonate as ascmi-solid'composition which is principally cellulose hydrate, and freefrom deleterious sulphur compounds, in an aqueous solution including anefiicient coagulating agent, and P0 ions in such relation with a sodiumderivative as to extract such sulphur compounds from thesulphocarbonatae into said aqueous solution and prevent precipitation ofsuch com pounds by holding them in said solution,

independently of said precipitated cellulose hydrate.

In testimony whereof, I have hereunto signed my name at Philadelphia,Pennsylvania, this eighth day of May, 1925.

WILLIAM MENDEL.

